FreeBSD Manual Pages

GETPROTOENT(3) BSD Library Functions Manual GETPROTOENT(3)
NAMEgetprotoent, getprotobynumber, getprotobyname, setprotoent, endprotoent
-- get protocol entry
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS#include <netdb.h>
structprotoent*getprotoent(void);
structprotoent*getprotobyname(constchar*name);
structprotoent*getprotobynumber(intproto);
voidsetprotoent(intstayopen);
voidendprotoent(void);
DESCRIPTION
The getprotoent(), getprotobyname(), and getprotobynumber() functions
each return a pointer to an object with the following structure contain-
ing the broken-out fields of a line in the network protocol data base,
/etc/protocols.
struct protoent {
char *p_name; /* official name of protocol */
char **p_aliases; /* alias list */
int p_proto; /* protocol number */
};
The members of this structure are:
p_name The official name of the protocol.
p_aliases A zero terminated list of alternate names for the protocol.
p_proto The protocol number.
The getprotoent() function reads the next line of the file, opening the
file if necessary.
The setprotoent() function opens and rewinds the file. If the stayopen
flag is non-zero, the net data base will not be closed after each call to
getprotobyname() or getprotobynumber().
The endprotoent() function closes the file.
The getprotobyname() function and getprotobynumber() sequentially search
from the beginning of the file until a matching protocol name or protocol
number is found, or until EOF is encountered.
RETURN VALUES
Null pointer (0) returned on EOF or error.
FILES
/etc/protocols
SEE ALSOprotocols(5)HISTORY
The getprotoent(), getprotobynumber(), getprotobyname(), setprotoent(),
and endprotoent() functions appeared in 4.2BSD.
BUGS
These functions use a thread-specific data space; if the data is needed
for future use, it should be copied before any subsequent calls overwrite
it. Only the Internet protocols are currently understood.
BSD June 4, 1993 BSD